Nothing new here-

"Missing Women of Asia"
""The phenomen of the missing women of Asia is a shortfall in the number of women in Asia relative to the number that would be expected if there was no sex-selective abortion or female infanticide or if the newborn of both sexes received similar levels of health care and nutrition."
The news" report is based on economist Amartya Sen, essay in NY Times Review of Books, 1990, and several other articles in peer-reviewed journals.

The selective process is well-known in history, and undoubtedly goes far back in pre-history. Not confined to Asia or to current times. I remember reading in grade school history about Spartans throwing unwanted females over a cliff.

The percentages vary, mostly according to food availability, but new abortion methods have changed them locally- China, e. g.

A turnaround, a decrease, is currently underway- several references on this, one being:
Das Gupta, Monica; Chung; Shuzho, 2009, Is There an Incipient Turnaround in Asia's "Missing Girl" Phenomenon?"

Laudably. China tries to decrease population growth by limiting families to one child. Abortion is well-accepted (it is not illegal in Canada-U. S. or major European non-Catholic countries).
One problem in China with the program is that now there are too few children to take care of an aging population and the state must pay for their care.

A decent article, with references, in Wikipedia-
"Missing Women of Asia."